The awareness of the presence of a visual stimulus on a blank background is primarily determined by the stimulus's physical contrast energy. However, the visual system's sensitivity to stimulus contrast can be modulated by the state of the observer. For example, spatial attention increases contrast sensitivity for stimuli appearing at the cued location. Here, we demonstrate that prior information about the orientation of a stimulus increases contrast sensitivity in simple detection tasks, for which orientation itself was irrelevant. In a first series of experiments, participants performed a spatial 4-AFC task, indicating the location of a Gabor patch that was sandwich masked by visual noise. Providing valid information about the orientation of the Gabor patch (e.g. "vertical") before stimulus presentation improved localization performance relative to a non-informative baseline condition and to a condition with invalid prior information. In a second series of experiments, we measured contrast detection thresholds for Gabor patches with no external noise added. Valid prior information about the orientation of the Gabors was associated with lower contrast detection thresholds. These findings indicate that prior information about specific stimulus features can dynamically enhance the effective signal of visual input matching the expected feature. Thus, feature-specific predictions do not only influence our ability to make feature discriminations, as shown previously, but also influence whether we consciously perceive a stimulus at all.